Yes, you need to have the source for the kernel available. It is not recommended to patch a Fedora kernel source also. You should download the current vanilla 2.5.15 kernel source from kernel.org to patch then build.
If you are not familiar with patching and building your own kernel then please read and review (yes, read it as many times as is needed for you to understand);
http://www.digitalhermit.com/linux/K...ild-HOWTO.html
The basic (for Red Hat based systems ) steps are;
1. download and extract the kernel source
2. copy the /boot/config-2.6.14-1.1656 (??) file to the /usr/src/linux-2.6.15 directory as .config
3. patch the kernel source according to the guide from the URL
make xconfig
make
make modules_install
make install
This does differ from the guide, but does work for Red Hat based systems.
If at first you do not compile a working kernel then try again, many have failed a few times when first reaching this milestone.